ANCHORAGE, Alaska (CNN) - Sen. Ted Stevens, convicted last month on seven federal corruption charges, held a slight lead Wednesday in his race for re-election, with the outcome still to be determined.

Stevens, who has represented Alaska almost 40 years and is the Senate's longest-serving Republican, was leading with 48 percent of the vote. His opponent, Anchorage Mayor Mark Begich, had almost 47 percent of the vote.

With 435 of 438 precincts reporting Tuesday night, Stevens led Begich by more than 3,300 votes, 106,351 to 102,998.

But, "there's still a lot to be counted," said Gail Fenumiai, director of Alaska's Division of Elections.

She said more than 40,000 absentee ballots, 9,000 early ballots, and many provisional ballots are yet to be tallied. Officials will try to count them over the next 10 days, she said.

Alaska has no provision for a runoff if no candidate gets at least 50 percent of the vote; whoever gets the most votes wins.

Defeated candidates may ask for recounts.

If the difference between them ends up within 20 votes, or less than one-half of 1 percent, the state would bear the cost of the recount, Fenumiai said.

Stevens, convicted in October for filing false statements on Senate financial disclosure forms, has said he will fight the verdict.

He issued a statement on October 27 saying the "verdict is the result of the unconscionable manner in which the Justice Department lawyers conducted this trial. I ask that Alaskans and my Senate colleagues stand with me as I pursue my rights. "

If he emerges as the winner, he would be sworn in to his new term in early January despite the conviction. A two-thirds vote of the Senate would be required to expel him.

It's not clear when an expulsion vote might happen. The Senate ethics committee won't say if it has started an investigation of Stevens but has made clear it will not necessarily wait for the appeals process before acting.

Even if Stevens' conviction is overturned on appeal, the ethics committee could recommend, and the full Senate could vote on, his expulsion. That's because the Senate could still decide his actions were not appropriate for a senator, even if he was not found guilty in court.

Democratic and Republican leaders have abandoned Stevens already.

"If Ted Stevens happens to be re-elected, I think he will be expelled from the Senate," Sen. John Ensign, the head of the National Republican Campaign Committee, said Tuesday night.

Republicans would prefer for Stevens to win the seat, because his subsequent explusion would bring on a special election that Republicans think they would win. A Begich victory, of course, would put a Democrat in the seat for the next six years.

A special election would be held 60 to 90 days after an expulsion.

The name of Alaska Gov. Sarah Palin - Sen. John McCain's running mate - would be among those sure to be mentioned as a possible candidate in a special election.

It is also possible, Fenumiai said, that Palin would appoint someone to fill the vacant Senate seat temporarily until the special election. Fenumiai believes Palin could appoint herself to the temporary post, but that move would require her to resign as governor.
–CNN's Ted Barrett and Joe Sterling contributed to this report